JP2003144113A - Free-oxygen absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a free-oxygen absorber easy to handle because of excellent flowability, excellent in packability and productivity, having large oxygen absorption capacity per unit volume, capable of being packaged in a compact form and undetectable even with a metal detector. SOLUTION: This oxygen absorber comprises as the support granular calcium silicate with an average particle diameter of >=100 μm obtained by granulating chemically synthesized calcium silicate with an average particle diameter of <=50 μm, and >=120 pts.wt. of an easily oxidizable organic composition supported on 100 pts.wt. of the granular calcium silicate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an oxygen absorbent.

[0002]

2. Description of the Related Art There is a technique using an oxygen scavenger as one of preservation techniques for foods, pharmaceuticals, etc., and it is used for preventing mold, oxidation, discoloration and the like. The oxygen scavenger is usually a small oxygen absorber package in which easily oxidizable oxides are packaged in a small bag with a breathable packaging material, and it has gas barrier properties such as bags and containers that do not easily transmit oxygen along with stored items such as foods and pharmaceuticals. It is stored in a package and stored. As the oxygen scavenger, those mainly containing easily oxidizable inorganic substances such as iron, ascorbic acid compounds,
It is known that the main component is an easily oxidizable organic substance such as a polyhydric phenol compound and an unsaturated hydrocarbon compound.

An oxygen scavenger (hereinafter, referred to as an inorganic oxygen scavenger) whose main ingredient is an easily oxidizable inorganic substance such as iron is used to prevent the inclusion of metallic foreign substances in order to ensure the safety of preserved articles such as foods and pharmaceuticals. Not suitable because it is sensitive to metal detectors when inspecting with detectors. Therefore, an oxygen scavenger (hereinafter referred to as an organic oxygen scavenger) whose main component is an organic substance that is insensitive to the metal detector is used.

[0004] Organic oxygen scavengers are usually used in order to improve powder characteristics such as oxygen absorption activity, oxygen absorption rate and filling properties, in addition to the organic substance of the main component, and for example, JP-A-5-26937.
As described in Japanese Patent Publication No. 6, an inorganic filler and an inorganic carrier are used as the composition. However, when a natural product-derived inorganic carrier is used as this inorganic carrier, iron components such as iron oxide are contained as impurities, and there is a problem in that it is sensitive to a metal detector. Therefore, the natural inorganic carrier is washed with an acid to remove the iron component, but complete removal is difficult.

On the other hand, instead of the natural product inorganic carrier, a highly pure chemically synthesized inorganic carrier containing no iron component can be used. However, the powder characteristics in this case are small in particle size and often fine, resulting in low bulk density,
There are problems that the volume at the time of filling becomes large, the fluidity at the time of filling is bad, and powdering occurs at the time of filling.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above problems, is not detected by a metal detector, can carry a large amount of organic substances, and has an excellent deoxidizing ability per unit volume. Moreover, it aims at providing the oxygen scavenger which makes an organic substance a main ingredient.

[0007]

As a result of intensive studies on the above problems, the inventors of the present invention have been able to carry a large amount of organic substances without being detected by a metal detector, and The present invention has been completed by finding a deoxidizer having an excellent deoxidizing ability and containing an organic substance as a main component.

That is, the chemically synthesized average particle diameter is 50 μm.
An average particle size of 100 obtained by granulating the following calcium silicate
An oxygen scavenger characterized by comprising granular calcium silicate having a particle size of μm or more as a carrier, and supporting an organic oxidizable composition in an amount of 120 parts by weight or more based on 100 parts by weight of the above-mentioned granular calcium silicate was found. Completed the invention.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, a chemically synthesized inorganic carrier is used as a carrier, and a granular calcium silicate having an average particle size of 100 μm or more obtained by granulating calcium silicate having an average particle size of 50 μm or less is used as a carrier. It is essential that the organic oxidizable composition is supported in an amount of 120 parts by weight or more based on 100 parts by weight of the granular calcium silicate.

In the present invention, the calcium silicate as a raw material of the granular calcium silicate that serves as the carrier of the easily oxidizable composition is a chemically synthesized calcium silicate particle having an average particle size of 50 μm or less, and is generally white carbon. Includes what is called. Specifically, for example, there is a method of hydrothermally reacting a silicon raw material and quick lime under high temperature, high-pressure saturated steam and a method of reacting calcium sulfate and sodium silicate under hydrothermal conditions, and needle-shaped crystals depending on the manufacturing method. Crystal structures and amorphous materials such as plate crystals and petal crystals are generated,
Either can be used.

In the present invention, the above-mentioned calcium silicate is granulated, and then granular calcium silicate having an average particle diameter of 100 μm or more is used as a carrier (hereinafter, this carrier is referred to as “the carrier of the present invention”). By the granulation operation, an oxygen scavenger having good fluidity, free from powdering, easy to handle in packing material and high in packing density can be obtained. The particle diameter as used herein means the maximum length in a particle having a spherical shape, an amorphous shape, a prismatic shape, a cylindrical shape, or the like, and for example, 100 μm to 15 mm is preferable, and 300 μm to 10 mm is more preferable range. A particularly preferable particle diameter is 100 μm to 5 mm for substantially spherical particles, and 500 μm to 7 mm for irregularly shaped, prismatic, or cylindrical particles. Also, as a powder property of the oxygen absorber, particles having an average particle size of less than 100 μm are
It has insufficient fluidity and is not suitable for filling and packaging by high-speed automatic machines.

The obtained granular calcium silicate is dried, and then an easily oxidizable composition is supported to obtain the oxygen scavenger of the present invention. The loading method is a chemically synthesized average particle size of 50 μm.
The following powder of calcium silicate and an easily oxidizable composition are mixed and then granulated by a method such as rolling granulation or extrusion granulation, or chemically synthesized calcium silicate having an average particle diameter of 50 μm or less is mixed with water. Or mixing with alcohol, rolling granulation,
A method of granulating by a method such as extrusion granulation, drying and then impregnating the liquid oxidizable composition is appropriately used.

Further, a suitable binder may be added during granulation. As the binder, for example, polyvinyl alcohol, polyvinyl acetate, polyacrylic acid, synthetic polymer compounds such as polyurethane, methyl cellulose,
Examples thereof include cellulose compounds such as ethyl cellulose and carboxymethyl cellulose, natural compounds such as guar gum, xanthan gum, tragacanth gum, carrageenan, and sodium alginate.

In addition to this, additives may be added to accelerate the deoxidation reaction during granulation and to remove the odorous components generated by the deoxidation reaction. As the additive, alkali metal, or a compound of alkaline earth metal, iron salt, manganese salt, copper salt, transition metal salt catalyst such as cobalt salt, carbonic acid gas regulator such as carbonate, bicarbonate, activated carbon, Examples thereof include silica gel and zeolite.

The organic oxidizable composition supported on the carrier of the present invention comprises an organic compound which is the main agent of the oxygen scavenger and an additive which makes the main agent of the organic compound easily oxidizable chemically. Become. Examples of the organic compound which is the main agent of the oxygen scavenger include, for example, ascorbic acid and salts thereof, erythorbic acid and salts thereof, glycerin, ethylene glycol, propylene glycol, glucose, polyhydric alcohol compounds such as xylose, catechol, resorcin, hydroquinone, Examples thereof include phenolic compounds such as gallic acid, pyrogallol and tocopherol, unsaturated oils and fats such as vegetable oils, fish oils and tall oils, and unsaturated polymers thereof such as fatty acids, butadiene oligomers and isoprene oligomers. From the viewpoints of oxygen absorption performance, availability, price, etc., ascorbic acid and its salts, gallic acid and butadiene oligomers are preferable, and ascorbic acid and its salts are more preferably used.

As additives for making the above organic compounds chemically oxidizable, alkali metal or alkaline earth metal compounds, iron salts, manganese salts, copper salts,
Examples thereof include transition metal salt catalysts such as cobalt salts, carbonic acid gas regulators such as carbonates and bicarbonates, and water, and one or several kinds may be appropriately selected and used from these.

The oxidizable composition of the present invention may be used in an amount of 120 parts by weight or more based on 100 parts by weight of the carrier of the present invention. As a result, it is possible to obtain an excellent oxygen absorber having a large oxygen absorption amount even if the capacity is small. The easily oxidizable composition is preferably loaded on a carrier in a larger amount, and is preferably loaded in an amount of 150 parts by weight or more, more preferably 200 parts by weight or more, still more preferably 300 parts by weight based on 100 parts by weight of the carrier of the present invention. It is more than part by weight.

When the easily oxidizable composition is carried on the carrier of the present invention, it is preferable to impregnate the organic oxidizable composition in the form of an aqueous solution, slurry or oil. Further, if necessary, a deodorizing agent such as activated carbon and a powder filler as a fluidity improving agent may be added. As a method of addition, it is also possible to coat the surface of the oxygen scavenger or mix them as separate particles.

The carrier of the present invention can impregnate and adsorb a large amount of the easily oxidizable composition as a liquid as compared with the conventional carrier. As a result, it is possible to increase the oxygen absorption capacity per unit volume, and it is possible to obtain a smaller, easier-to-use and less expensive oxygen absorber.

The oxygen absorber of the present invention is used as an oxygen absorber package by wrapping it with a breathable packaging material. As the breathable packaging material, paper, resin film, non-woven fabric, perforated resin film, or a laminate of these is used. The oxygen scavenger package obtained by wrapping the oxygen scavenger of the present invention in a breathable packaging material uses a large amount of oxygen scavenger and is detected by a metal detector even when a large oxygen scavenger package is prepared. Never.

[0021]

EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. The experimental method used in the present invention is described below. (Flowability of oxygen absorber) Good when oxygen absorber smoothly falls through the funnel of the equipment specified in JIS K-6721 (○)
The case where the dropping stopped or the case where the dropping did not occur at all was regarded as defective (x). (Oxygen absorption amount per unit volume) 2 g of the oxygen scavenger was filled in a bag formed with polyethylene with perforation inside using a packaging material obtained by laminating perforated polyethylene / paper / perforated polyester in this order. It closed by heat sealing and it was set as the oxygen absorber package. This oxygen absorber package was enclosed in a gas barrier bag (polyester / aluminum foil / polyethylene laminate) together with 2 liters of air and kept at 25 ° C for 2 hours.
The oxygen concentration in the gas barrier bag after standing for one day was analyzed by gas chromatography to calculate the oxygen absorption amount per unit weight (1 g) of the oxygen scavenger. (Mass Density of Deoxidizer) According to JIS K-6721, the oxygen scavenger was put in a 100 ml container, and its weight was measured to calculate the mass density. (Metal detector suitability) Put 4g and 20g of oxygen absorber into polyethylene bag, detect iron ball of 0.6mmφ,
It was applied to a metal detector (manufactured by Anritsu Industry Co., Ltd.) adjusted to the condition that a 0.5 mmφ iron ball was not detected. The case where it was not detected was marked (○), and the case where it was detected was marked (×).

Example 1 0.5 kg of chemically synthesized calcium silicate having an average particle diameter of 25 μm, 1.8 l of water and 0.08 kg of polyvinyl acetate emulsion as a binder were mixed, and then a hole having a diameter of 1.0 mm was formed. It was extruded and granulated from a punching plate to obtain 2.3 kg of a cylindrical granular material having a length of 2 to 5 mm. After passing this through a sieving machine, using a fluidized bed drier, hot air drying was carried out at 100 ° C. for 30 minutes until substantially free of water to obtain 0.5 kg of carrier. On the other hand, 10 kg of a 50% aqueous solution of sodium ascorbate was added to ferrous sulfate 7
0.6 kg of water salt and 0.1 kg of sodium carbonate were dissolved to prepare an easily oxidizable composition in the form of an aqueous solution.
Sodium ascorbate solution 0.33 for 1 kg
kg was added little by little and impregnated while mixing to obtain an oxygen absorber. The fluidity, oxygen absorption amount, bulk density and suitability for metal detector of the obtained oxygen scavenger were analyzed by the above method. The results are shown in Table 1.

From Table 1, it can be seen that the fluidity of the oxygen scavenger, the amount of oxygen absorbed per unit volume, the bulk density and the suitability for a metal detector are excellent.

COMPARATIVE EXAMPLE 1 0.1 kg of the synthetic calcium silicate powder of Example 1 having an average particle size of 25 μm was impregnated with the easily oxidizable composition used in Example 1 in the same manner as in Example 1, but immediately. Agglomerates were generated while generating heat. The fluidity, oxygen absorption amount, bulk density and suitability for metal detector of the obtained oxygen absorber were analyzed in the same manner as in Example 1. The results are shown in Table 1.

It can be seen from Table 1 that if the finely powdered synthetic calcium silicate is not granulated and directly impregnated with the easily oxidizable substance, the fluidity is extremely poor and only a powder that cannot be filled is obtained.

Example 2 As in Example 1, 1.0 kg of chemically synthesized powdered calcium silicate having an average particle size of 25 μm was added to 2.6 kg of the oxidizable composition used in Example 1, and polyvinyl acetate as a binder. After mixing 0.16 kg of the emulsion and mixing with a mixer, spherical particles having an average particle size of 1.0 mm were formed using a rolling granulator. Subsequently, the particle surface was coated with 0.05 kg of gypsum to obtain an oxygen absorbent. The fluidity, oxygen absorption amount, bulk density and suitability for metal detector of the obtained oxygen absorber were analyzed in the same manner as in Example 1. The results are shown in Table 1.

From Table 1, it can be seen that the fluidity of the oxygen scavenger, the oxygen absorption amount per unit volume, the bulk density, and the suitability for metal detectors are good.

Comparative Example 2 Wollastonite powder, which is a natural calcium silicate, 0.1 k
It was attempted to impregnate g with the easily oxidizable composition used in Example 1 in the same manner as in Example 1, but almost no impregnation was possible.

Comparative Example 3 0.1 kg of the powdery natural zeolite and 0.12 kg of the easily oxidizable composition used in Example 1 were mixed by a mixer, but a slurry was formed and granulation was impossible. Therefore, the amount of the easily oxidizable composition was reduced to 0.04 kg, and after mixing, spherical particles having an average particle size of 1.5 mm were formed using a rolling granulator. Subsequently, the particle surface was coated with 0.005 g of gypsum to obtain an oxygen absorber. The fluidity, oxygen absorption amount, bulk density and suitability for metal detector of the obtained oxygen absorber were analyzed in the same manner as in Example 1. The results are shown in Table 1.

It can be seen from Table 1 that when natural zeolite is used instead of synthetic zeolite, it is sensitive to metal detectors because it contains an iron component.

[0031]

[Table 1]

[0032]

EFFECTS OF THE INVENTION The oxygen scavenger of the present invention has good fluidity by selecting calcium silicate synthesized on an inorganic carrier and applying a granulation operation, so that it is easy to handle, excellent in fillability and productivity, and unit volume. A large amount of oxygen absorbed per unit makes it possible to package an oxygen absorber with a compact shape, and realizes an oxygen absorber that is not detected by a metal detector.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masateru Nagata             6-1, 1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas             Chemical Co., Ltd. Tokyo factory F-term (reference) 3E067 AA05 AB97 BA12A BA17A                       BB01A BB06A BB14A BB25A                       BC04A CA03 EA06 FA01                       FC01 GD07                 4B021 MC04 MK08 MK17 MK20 MK21                       MP08                 4G066 AA30C AB01B AB06B AB07B                       AE19C BA09 BA12 BA20                       CA37 DA01 EA07 FA03 FA21                       FA27 FA28 FA37

Claims (3)

[Claims] 1. An organic oxidizable composition comprising a granular calcium silicate having an average particle size of 100 μm or more obtained by granulating chemically synthesized calcium silicate having an average particle size of 50 μm or less An oxygen scavenger, which is carried by 120 parts by weight or more with respect to 100 parts by weight of calcium. 2. An organic oxidizable composition comprising at least one organic oxidizable compound selected from the group consisting of polyhydric alcohols, polyhydric phenols, unsaturated fats and oils, unsaturated fatty acids and unsaturated polymers. The oxygen scavenger according to claim 1, which comprises a volatile composition. 3. An oxygen scavenger package comprising the oxygen scavenger composition according to claim 1 and claim 2 packaged in a breathable packaging material.